Dishwasher Not Draining — Step-by-Step Fix

If your dishwasher finishes the cycle with water pooled at the bottom, the cause is almost always one of five things: a clogged filter, a kinked drain hose, a failed drain pump, a blocked garbage-disposal connection, or a stuck check valve. Work through them in that order — three of the five are free fixes.

If your dishwasher finishes the cycle with water pooled at the bottom, the cause is almost always one of five things: a clogged filter, a kinked drain hose, a failed drain pump, a blocked garbage-disposal connection, or a stuck check valve. Work through them in that order — three of the five are free fixes.

What's actually broken when a dishwasher won't drain?

A dishwasher drains by firing a small electric pump at the end of each cycle. That pump pushes water up through a rubber hose, over a high loop under your countertop, and into either the kitchen drain or the side of your garbage disposal. Anywhere along that path, a blockage stops the water from leaving the tub — and because the pump is sized for a clean line, even a small restriction is enough to defeat it.

The path is short and there are only five meaningful failure points: the filter and drain basket at the bottom of the tub (where food scraps collect), the drain hose itself (which kinks or clogs with grease), the drain pump (which burns out or jams on debris), the disposal connection (commonly blocked by a knockout plug that was never removed at install), and the check valve (which stops dirty drain water from flowing back in). Rule them out in order and you'll find the problem in under half an hour. None of this involves gas or refrigerant, so the DIY ceiling is higher than on a fridge — but water and electricity share the same cabinet, so power off first, always.

Diagnose your dishwasher in five steps

Go in order. Each step either fixes the problem or eliminates a cause and points you at the next.

1. Turn off power and remove the standing water

Flip the dedicated breaker for the dishwasher, or unplug it if it's on a cord. This isn't optional — you're going to reach into a tub with water in it, and the drain pump sits inches away from your hands. With power off, scoop the standing water out with a cup and soak up the last of it with towels. You need a dry, visible drain area to diagnose anything below it.

2. Clean the filter and drain basket

At the bottom of the tub, centred or at the back, is a cylindrical filter — usually a twist-lock or a single screw. Lift it out and you'll see a flat drain basket underneath. Rinse the filter under hot running water, scrub the fine mesh with an old toothbrush or a soft dish brush, and pick any debris out of the basket. You'll find the usual suspects: labels from tomato cans, fruit stickers, olive pits, seeds, pieces of glass, fragments of chicken bone. A blocked filter is the single most common drain failure we see — and many homeowners have never cleaned theirs because the manual got thrown out years ago. Reinstall the filter snugly; a loose filter lets debris bypass into the pump and causes the next failure on this list.

3. Inspect the drain hose for kinks or clogs

Pull the dishwasher forward out of the cabinet — just enough to see the back. Trace the corrugated drain hose from the bottom of the dishwasher up into the sink cabinet. Look for obvious kinks where the hose bends sharply, especially right at the exit from the dishwasher body. Confirm the high loop: code in most of the GTA requires the drain hose to loop up under the countertop before it drops to the disposal or drain connection, which prevents sink water from siphoning back into the tub. If the hose looks fine externally, disconnect it at the sink end (have a bucket ready), and run water through it from a tap or flush it with a coat hanger. Grease, toothpicks, and bits of plastic film are common internal clogs — especially on units more than a few years old.

Book a technician if the clog won't clear.

4. Check the drain pump for obstructions or burnout

With the filter still out, shine a flashlight into the sump at the bottom of the tub. You're looking at the intake for the drain pump. Obstructions love this spot — shards of glass, twist ties, fruit stickers, popcorn kernels, chicken bones. A shard wedged against the impeller stops it dead. Use long tweezers or needle-nose pliers (power still off) to remove anything visible. If the sump is clear but the pump makes a loud hum or a burning electrical smell when the cycle tries to drain, the motor windings are shot and the pump needs replacing — that's a parts-on-hand service call, typically 1–2 hours depending on the brand. Access varies: on some units you reach the pump from underneath; on others you pull the dishwasher out and tip it to get at it.

5. Test the check valve and disposal connection

Two easy-to-miss causes live here. First, if your dishwasher drains into a garbage disposal, confirm the knockout plug inside the disposal inlet was removed when the disposal or dishwasher was installed. It's a factory-sealed plastic disc that a new disposal ships with, and it has to be punched out — if whoever installed it forgot, your dishwasher has never had anywhere to drain to. You'll know by disconnecting the hose at the disposal and shaking the plug out. Second, check the check valve on the drain line — a small one-way flap that stops dirty sink water from backwashing into the tub. A stuck-closed valve blocks drainage; a stuck-open valve lets sink debris and grease into your clean dishes. Replacement is a cheap part if your unit has a serviceable valve.

The four parts that fail most often

Filter and drain basket clog

The number-one cause, by a wide margin. Food scraps, labels, and glass collect in the filter mesh and the basket underneath. On units without a hard-food disposer (most modern European-brand dishwashers), the filter is entirely the homeowner's job to clean. Typical repair time: 10 minutes, zero cost, if you catch it early.

Drain-hose kink or internal clog

Second most common. The hose bends sharply where it exits the dishwasher, or it fills with a grease film over years that eventually restricts flow. Hard-water homes in York Region see faster mineral buildup inside the hose too. A hose swap is inexpensive and usually a 30–45 minute job; a hose flush is faster still.

Drain pump failure

Either a mechanical jam (glass, bone, wire tie through the impeller) or an electrical burnout (motor windings open). Jams are free once you get to the impeller. A failed motor means a pump replacement — typical repair is 1–2 hours including pulling the unit out, and part availability varies by brand.

Garbage-disposal connection

Almost always the knockout plug that was never removed at install. We see this on fairly new installs where a dishwasher and a disposal were added at the same time and the installer missed the step. The fix is a five-minute disconnect-and-punch once you know where to look.

Can you fix this yourself?

Basic DIY — screwdriver and a towel

Filter cleaning, drain-hose inspection and straightening, removing visible obstructions from the sump, and checking the knockout plug are all basic DIY. No electrical testing, no part ordering. Power off, reach in, clear, reassemble. If you've never done it before, give yourself half an hour and a good flashlight.

Mid-level DIY — part ordering and teardown

Drain pump replacement is mid-level. You need to identify the correct part for your dishwasher — serial number and data plate, not "the one that looks like mine online" — order it, pull the dishwasher out, sometimes tip it on its back, remove the old pump, and wire in the new one. Doable for a confident DIYer. Slow and frustrating if it's your first time. Brand matters: some units are assembly-line friendly, others require disassembling half the door to reach a clip.

Call a technician immediately if:

• The pump is making a burning smell or a grinding sound under power.
• You suspect the control board (cycle won't advance, drain never fires, random error codes).
• The unit is over 10 years old and the repair involves the pump or the board.
• Water is visibly leaking from the unit onto the floor or into the cabinet below.
• You can't identify where the drain line goes or how the unit is plumbed in.

Frequently asked questions

Local service and next steps

Appliances City Wide services the 22 GTA cities. Hard water in York Region accelerates mineral buildup inside drain hoses and around pump seals — Vaughan, Markham, and Richmond Hill homes see drain issues a year or two sooner than Toronto and Mississauga homes on softer municipal water. Either way, the diagnostic is the same. Every repair includes a 1-year parts-and-labour warranty at no extra charge. See the Toronto service area page for neighbourhoods served, or jump to our dishwasher repair service for pricing and what to expect on the visit.

Frequently asked questions